Pump unit

ABSTRACT

An immersible centrifugal pump unit which when lifted out of and lowered into a liquid is steered on a guide. The pump has a liquid outlet with a connecting flange parallel to the guide. The flange is sealed against a flange of an outlet pipe when the pump is submerged and brought into contact with the outlet pipe. A gripper on the pump engages the flange on the outlet pipe to hold the pump flange against the flange of the outlet pipe. The uppermost part of the opposing flange surfaces are at a level not higher than the lowermost point of engagement of the gripper and the flange of the outlet pipe.

Carlsson [151 [451 Apr. 1, W2

[54] PUMP UNIT [72] Inventor: Konrad Valdemar Sweden Carlsson, Solna,

[30] Foreign Application Priority Data Apr. 1, 1969 Sweden ..4655/69 [56] References Cited UNITED STATES PATENTS 3,136,259 6/1964 Bood ..417/360 3,234,885 2/1966 Englesson ..222/333 X FOREIGN PATENTS OR APPLICATIONS 1,187,931 2/ 1965 Germany ..417/360 Primary ExaminerRobert M. Walker Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT An immersible centrifugal pump unit which when lifted out of and lowered into a liquid is steered on a guide. The pump has a liquid outlet with a connecting flange parallel to the guide. The flange is sealed against a flange of an outlet pipe when the pump is submerged and brought into contact with the outlet pipe. A gripper on the pump engages the flange on the outlet pipe to hold the pump flange against the flange of the outlet pipe. The uppermost part of the opposing flange surfaces are at a level not higher than the lowermost point of engagement of the gripper and the flange of the outlet pipe.

3 Claims, 1 Drawing Figure PUMP UNIT The invention relates to a pump unit immersed in a liquid, which can be easily removed from the liquid for maintenance of the unit.

In the case of pump units intended to work fully or partially immersed in the pumped medium there are great difficulties in maintenance if the units are permanently installed. In order to eliminate these drawbacks, the method of arranging pump units on guides is known, the units being lowered into the pumped medium along the guides and being so arranged that in their immersed position they bear against an outlet pipe for the pumped medium and in this position are as far as possible tightly sealed to the outlet pipe without being attached to it by means, for example, of screws.

Such known arrangements admittedly allow the pump units to be hoisted up relatively easily from the pumped medium for.

purposes of maintenance, but certain drawbacks nevertheless exist, e.g. difficulties in getting the pump units to seal tightly to the outlet pipes of the immersed units.

Devices of this kind are known in which the flanges which connect a pump unit to an outlet pipe form a given angle with a vertical plane. The advantage of this is that the pump unit, in its immersed position in the pumped medium seals against the outlet pipe under the influence of at least part of the units gravity. This ensures a good seal between pump and outlet pipe provided that the connecting flange of the outlet pipe is essentially free from dirt. In installations designed for the pumping of polluted liquids, however, pollution is deposited chiefly on the flange of the outlet pipe and it is difficult to get the pump unit to seal tightly against the outlet pipe after the performance of maintenance.

Other devices of this kind are known in which the sliding shoes which run on the guides are articulately connected to the pump unit, the pump unit-after being immersed in the pumped mediumbeing caused to rotate slightly round an essentially horizontal shaft and being lowered against the connecting flange of the outlet pipe. In such devices as well the gravity of the pump unit is used to achieve a seal against the connecting flange through the fact that a given torque arises round the shaft around which the sliding shoes are rotatably arranged. In such devices as well a seal is obtained between the pump unit and outlet pipe only on condition that the connecting flanges are free from dirt.

An articulated joint between the sliding shoes and guide involves another disadvantage, namely that the pump unit, for example after maintenance, is difficult to fit to the guide again. For this purpose not only must the pump unit be kept in a proper position for fitting to the guide but the sliding shoes must be rotated so as to be properly positioned in relation to the guide. Locking effects may then readily arise, which greatly complicate the fitting of the sliding shoes to the guide.

In the attempt to produce a device in which dirt from the connecting flanges is automatically scraped off the connecting flanges in conjunction with the immersion of the pump units, trials have been made to arrange the connecting flanges on a plane essentially parallel to the guide. During immersion of a pump unit its connecting flange is caused to scrape against the connecting flange of the outlet pipe, so removing the dirt. But with such an arrangement the gravity of the pump unit cannot be used for pressing the connecting flanges together, so that the seal is not so satisfactory as in devices which have obliquely set flanges or in devices in which the pump unit is rotatable around an essentially horizontal shaft.

In order to eliminate this drawback a method is known in which the pump units are furnished with grippers which grip around the connecting flange of the outlet pipe. The grippers and/or connecting flange of the outlet pipe are suitably furnished with oblique shoulder surfaces so that a wedging effect arises between the gripper and the connecting flange. This arrangement of a pump unit has, however, proved to be attended by a drawback of such significance that it has not come into practical use. Its disadvantage is that the pump unit is locked so effectively to the outlet pipe that it is extremely difficult to remove. The locking action is due chiefly to the fact that the lifting force exercises some torque on the pump unit, the which torque is partially taken up by the grippers. The torque varies greatly in magnitude, depending, inter alia, on the direction of the lifting force. Owing to external conditions the lifting force cannot always be applied fully vertically and the moment of the force causes a locking effect on grippers and connecting flanges.

The present invention is intended to eliminate these disadvantages and consists of a pump unit immersible in a liquid, comprising a liquidtight, enclosed electrical motor and a pump, preferentially a centrifugal pump. The unit is arranged in the known manner to be steered into a guide device in the course of being raised from and lowered into the liquid. The liquid outlet of the pump in the fully immersed position of the pump unit is caused, by a flange essentially parallel with the guide, to seal against a flanged outlet pipe for the liquid under the influence of a gripping device engaging with the flange of the outlet pipe. The invention is characterized chiefly in that the uppermost portion of the opposing flange surfaces is situated at a level below or on the level with the bottommost point of engagement of the gripping device and the flange of the outlet pipe.

The connecting flange of the outlet pipe should suitably be designed so that the uppermost section of the surface intended to bear against the connecting flange of the pump unit is chamfered so as to engage with a corresponding chamfer in the lower section of the connecting flange of the pump unit as the pump unit is lowered. This ensures that the connecting flange of the pump unit, during lowering of the unit, slides down along the connecting flange of the outlet pipe.

The connecting flanges are pressed together when the gripper on the pump unit grips around the connecting flange of the outlet pipe. The gripper and the surface of the connecting flange on the outlet pipe on the side opposite the pump unit, with shoulder surfaces oblique to a vertical line, should preferably be shaped so that a wedging eflect arises when the pump unit is lowered to the outlet pipe. Owing to the gravity of the pump unit the two connecting flanges are thereby pressed together.

With a pump unit according to the invention an effective seal is obtained between the outlet of the pump unit and the outlet pipe for pumped liquid. At the same time, the pump unit can be easily lifted out of the liquid without the risk of locking even if the lifting force is not vertically directed. As noted above, a further advantage is gained in that any dirt on the connecting flanges is scraped off when the pump unit is lowered into its intended position.

One embodiment of the invention will now be described with reference to the attached drawing.

The drawing shows a pump unit 3, which can be raised and lowered along a guide 9. The pump unit 3 is steered in the guide 9 by means of a steering device rigidly attached to the pump unit 3 and having sliding shoes 7, 8. When the pump unit 3 is in its immersed position, a flange 10 arranged at the outlet of the pump is brought into engagement with a flange l 1 on an outlet pipe 2 for the pumped medium.

. The connecting flanges 10 and 11 are chamfered on their opposing surfaces, the chamfer on the connecting flange 10 being situated on its bottommost section and the chamfer on the connecting flange 11 on its upper section. The upper section of the connecting flange 11 is chamfered also on its surface on the side opposite from the pump unit, the which chamfer is designed to engage with an oblique shoulder surface on the gripper 4. In this way a wedging effect is obtained on immersion of the pump unit, so ensuring a good seal between flanges l0 and 11.

The gripper 4 and the connecting flanges 10, 11 are shaped so that the gripper 5 cannot be carried further down towards the outlet pipe 2 than that its free end 6 is on a level above or possibly on a level with the uppermost section 5 of the engaging surfaces between the connecting flanges 10, 11. The advantage of this is that the pump unit can always be released from the outlet pipe even if the pump unit is lifted with a force which forms a certain angle with a vertical line. As a certain play cannot be avoided between the sliding shoes 7 and guide 9, the pump unit has a slight rotary movement round a shaft perpendicular to the plane of the drawing. When lifting of a pump unit of a type, this rotation means that the pump unit is rigidly locked to the flange of the outlet pipe. With a form of the gripper 4 and the connecting flanges l and 11 in accordance with the invention, on the other hand, no locking of the pump unit takes place when it is acted upon by a lifting force.

Although the invention has been described with reference to one of its embodiments, it can be arbitrarily varied within the scope of the subsequent claims.

What 1 claim is:

1. An immersible pump unit for connection to an outlet pipe having a first flange, said pump unit comprising:

a. a pump;

b. a liquidtight electric motor;

c. guide means for guiding said unit for engagement with said outlet pipe;

d. a second flange on the outlet of said unit and parallel to said guide means; and

e. gripper means coupled to the exterior of said unit for engaging said first flange such that said first flange and said second flange are held together to form a liquidtight passage between said outlet pipe and said unit, and the lowermost point of engagement between said gripper means and said first flange is above or at the highest point at which said first and second flanges come together and said lowermost point is above the upper surface of said outlet whereby mutual interlocking between said first and second flanges is prevented.

2. The apparatus as set forth in claim 1 wherein said first flange is chamfered at its upper portion and said second flange is chamfered at its lower portion whereby the upper portion of said first flange and the lower portion of said second flange temporarily engage when said unit is moved into engagement with said outlet pipe.

3. The apparatus as set forth in claim 1 wherein the surface of said first flange furthest from said unit includes a shoulder surface oblique to the surface nearest the unit such that said gripper means engages said first flange on said shoulder thereby forming a tight seal between said first and second flanges. 

1. An immersible pump unit for connection to an outlet pipe having a first flange, said pump unit comprising: a. a pump; b. a liquidtight electric motor; c. guide means for guiding said unit for engagement with said outlet pipe; d. a second flange on the outlet of said unit and parallel to said guide means; and e. gripper means coupled to the exterior of said unit for engaging said first flange such that said first flange and said second flange are held together to form a liquidtight passage between said outlet pipe and said unit, and the lowermost point of engagement between said gripper means and said first flange is above or at the highest point at which said first and second flanges come together and said lowermost point is above the upper surface of said outlet whereby mutual interlocking between said first and second flanges is prevented.
 2. The apparatus as set forth in claim 1 wherein said first flange is chamfered at its upper portion and said second flange is chamfered at its lower portion whereby the upper portion of said first flange and the lower portion of said second flange temporarily engage when said unit is moved into engagement with said outlet pipe.
 3. The apparatus as set forth in claim 1 wherein the surface of said first flange furthest from said unit includes a shoulder surface oblique to the surface nearest the unit such that said gripper means engages said first flange on said shoulder thereby forming a tight seal between said first and second flanges. 